We developed a novel low-radiation-absorbent lok-bar (HM-bar) that is used to secure the immobilizers to the couch. The aim of this study was to investigate the X-ray scattering and absorption properties of the HM-bar in computed tomography (CT) simulation and radiotherapy dose delivery using the Varian Exact™ lok-bar (VL-bar) as a benchmark. CT images were obtained with or without lok-bar, and...

The concept of diagnostic reference levels (DRLs) is recognised as an efficient and powerful tool in optimization of diagnostic X-ray examinations. Norway was one of the pioneer countries in establishing national DRLs, but focus on implementation and use of DRLs locally at the clinics in optimization purposes has been absent until now. The aim of this study was to map the dose levels and optimi...

Introduction: The rapid use of computed tomography (CT) scan is of great concern, due to increase in patients’ dose. Optimization of CT protocol is a vital issue in dose reduction. This study aimed to optimize radiation dose in cranial CT and assess modifications in image quality under radiation dose reduction. Material and Methods: A poly(me...

Iterative statistical X-ray CT reconstruction algorithms can improve image quality for low dose scans. Unfortunately, their clinical utility has been hampered by their enormous computational requirements; typical low-dose reconstructions require about an hour on commercial systems. Most existing parallel implementations use a shared memory programming model, limiting available parallelism. We i...

Objective of this work is to evaluate radiation exposure from X-ray examinations in a large paediatric hospital in Serbia, including radiographic, fluoroscopic and computed tomography (CT) examinations in four age groups: 0-1, 1-5, 5-10 and 10-15 y. Incident air kerma was assessed for the following radiographies: chest (AP, PA, LAT), spine (AP, LAT), pelvis (AP), urinary tract (AP, PA) and skul...

This study presents a 3D dose mapping of complex dose distributions using an x-ray computed tomography (CT) polymer gel dosimetry technique. Two polyacrylamide gels (PAGs) of identical composition were irradiated with the same four arc stereotactic treatment to maximum doses of 15 Gy (PAG1) and 8 Gy (PAG2). The PAGs were CT imaged using a previously defined protocol that involves image averagin...

The finite width of the X-ray beam determined by the source and detector aperture limits the resolution of computed tomography (CT) images. Improved resolution can be obtained by reducing the width of the detector, but at a cost in dose utilization efficiency. We show that it is possible to improve the resolution in a CT image with a minimum cost in dose efficiency by varying the sensitivity of...